-LRB- CNN -RRB- -- The Pentagon must hold down its spending and make choices that will anger `` powerful people '' in an era of economic strain , Defense Secretary Robert Gates said in a weekend speech in Kansas .

Increasing health care costs , a top-heavy uniformed and civilian management force , and big-ticket weapons systems are swelling the military 's budget at an `` unsustainable '' rate , Gates said . In response , Gates said , he has ordered the Defense Department 's military and civilian leaders to find savings of 2 to 3 percent -- more than $ 10 billion of the Pentagon 's roughly $ 550 billion base budget -- and shift spending toward war-fighting costs .

`` These savings must stem from root-and-branch changes that can be sustained and added to over time , '' he told an audience Saturday at the Eisenhower Presidential Library in Abilene . `` Simply taking a few percent off the top of everything on a onetime basis will not do . ''

On his way out of office in 1961 , President Eisenhower -- the former general who led allied forces in Europe during World War II -- warned of the expanding influence of what he called the `` military-industrial complex . '' Nearly 50 years later , Gates invoked that history to warn that the cuts on the way `` will displease powerful people , both inside the Pentagon and out . ''

The U.S. defense budget has more than doubled since the September 11 , 2001 , attacks on New York and Washington and the 2003 invasion of Iraq . Since taking office in 2006 , Gates has managed to cut some of the Pentagon 's major weapons systems , but efforts to kill other programs have been defeated under heavy pressure from military contractors and members of Congress .

`` Given America 's difficult economic circumstances and parlous fiscal condition , military spending on things large and small can and should expect closer , harsher scrutiny , '' he said . `` The gusher has been turned off , and will stay off for a good period of time . ''

Retired Army Brig. Gen. Mark Kimmitt , a former U.S. military spokesman in Iraq , told CNN that Gates is trying to preserve U.S. combat power in the face of increasing costs .

`` He sees the political winds and recognizes he will not be able to get the budgets that he needs , '' Kimmitt told CNN . `` What he wants to do is protect the muscle . By cutting away at some of the fat , he can keep the money necessary to keep the constantly increasing budget to maintain a strong and ready force . ''

Gates acknowledged that many of his predecessors have tried and failed to do the same thing . But he said the U.S. force structure should be reviewed in `` the wider , real-world context '' and was probably out of scale to existing threats .

`` For example , should we really be up in arms over a temporary projected shortfall of about 100 Navy and Marine strike fighters relative to the number of carrier wings , when America 's military possesses more than 3,200 tactical combat aircraft of all kinds ? '' Gates asked . `` Does the number of warships we have and are building really put America at risk when the U.S. battle fleet is larger than the next 13 navies combined , 11 of which belong to allies and partners ? Is it a dire threat that by 2020 the United States will have only 20 times more advanced stealth fighters than China ? ''

Gates said defense spending was roughly twice the share of the U.S. economy in Eisenhower 's day -- `` but today , we face a very different set of American economic and fiscal realities . ''

`` As a matter of principle and political reality , the Department of Defense can not go to America 's elected representatives and ask for increases each year unless we have done everything possible to make every dollar count , '' he said .

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Gates says he 's ordered officials to find savings of 2 to 3 percent in Pentagon budget

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Defense secretary wants `` root-and-branch '' changes , not just onetime cuts

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The cuts on the way `` will displease powerful people , '' Gates says at Eisenhower libary

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Goal is to shift Pentagon 's $ 550 billion annual spending toward war-fighting costs